quote Originally posted by maddoggie: I've been looking at the STS turbo systems design. The remote mount would seem to help with a couple potential problems with turbos....What are your thoughts?

On the "STS Turbo" website ( http://www.ststurbo.com ), it appears that their claim to fame of "lowest intake air temps in the industry" (which sounds like a good thing) is indeed due to where their turbo is located --- typically under the chassis --- rather than inside a hot engine compartment.

I've never used an STS turbo, but on the face of it at least, it sounds interesting.

quote Originally posted by Hudini: I hope you mean a turbo Fiero with decent fuel economy. Lol, hard to keep ones foot out of it when it's so much fun. I do have a Volvo S40 with a 1.9L turbo and it gets 34mpg highway. That's 75mph, 4 people, in the summer with A/C on. I have driven this car from Tennessee to Florida several times and it rocks. The 160mph speedo may be a bit optimistic.

That's the really nice part about having the ability to get the EXACT turbo for your design as well as the right transmission,etc.... your Volvo is designed to not be in boost at highway cruise. A fiero and almost all other aftermarket installs using the closest available turbo typically ends up having a lower spool up speed for the turbo and you end up in some kind of boost at highway speed. this would be a major problem in a fiero with a standard 3 speed automatic as the rpm's at cruise would be right where you wanted boost to be at anyways. Volvo in their wisdom made a great working turbo engine system and then gave it the right transmission to make the rpm's sit where you get no or minimal boost at highway cruise. The 4T60 upgrade on the fiero can help this quite a bit for the automatic cars.

Problem is I want my turbo to start spooling up at lower rpm. I want that low end grunt that the 3.4 has tons of to get a kick in the pants to get the most out of a turbo in an automatic. I will probably have to give up on the low rpm boost and go for a standard boosting starting at 3500. which if I mash it to the floor should not dip too far below if my shift points are set up right. (4T60E would be perfect for this, racing shift points or economy shift points at the flick of a switch on the controller.)


Next installment Ignition timing.

quote Originally posted by timgray: ..A fiero and almost all other aftermarket installs using the closest available turbo typically ends up having a lower spool up speed for the turbo and you end up in some kind of boost at highway speed. this would be a major problem in a fiero with a standard 3 speed automatic as the rpm's at cruise would be right where you wanted boost to be at anyways...

Please, consider the throttle position also. Turbo works from exhaust gases, not rpm.

3800 S1 engine for example can have VE of 80% @ 2000 and VE of 60% @ 4000 so the engine troughput increases only 50% over that area.
If the turbo makes first lb @ WOT @ 2000 then the same happens (1lb of boost) at 66% throttle(engine air restriction actually.) at 4000rpm.
So below that you are not making any boost.

I finally got my T3 installed along with a new Comp Cams 260H, cam bearings, rod bearings, main bearings, and a high volume oil pump. I am very, very pleased with the power this car produces with the 3.4L OHV engine. It absolutely screams. And it just pulls and pulls. Makes about 10psi of boost with no knock on premium gas. The wastegate actuator has been removed and the wastegate wired closed as I want all the boost the little T3 can make.

quote Originally posted by timgray: Turbo lag is of no real concern on the street as seen by the STS turbo and mounting them over 6 feet away from the engine. Honestly mounting your turbo lower down by the cat will give you no performance problems. The Turbo on big engine cars when mounted what is considered close is farther away than that.

(I've never quoted anybody as yet, I hope that this is correct.)
I was thinking of another benefit in moving the turbo past the cat. The cat might act as a sort of filter. Less trash through the turbo=less wear on the spool and bearings.

[This message has been edited by maddoggie (edited 04-08-2008).]

With space in the engine compartment to consider, I still think putting the turbo(s) down where the stock muffler is would be useful. Yes you would need a sump pump but from what I've seen with Corvettes, you wouldn't need to run a muffler (or would our short exhaust systems negate that?) If it's still too loud you might be able to fit some glass packs in somewhere. It all depends on how the exhaust is run of course.

The intake might be tricky with this setup though. You could put a scoop that got air from under the car but we wouldn't want too much hanging under our cars (they're low enough as it is). Otherwise you'd have to run some pipe around the tires and avoid the hot engine.

quote Originally posted by MordacP: I believe an automatic tranny shouldn't be any problem with a turbo. I would vastly prefer a manual because you have more control over your boost and engine speed. But an auto will work fine.

I would definitely have a internal wastegate on the turbo for the auto so when it shifts it won't blow the head gasket with boost. Even though the shifts are tight. But with it being internal there will be almost no lag.... Would this be a good assessment? I'm sure the computer would have to be tuned for the auto, NO?

Never do a boost install without a wastegate, they are cheap, easy to install and cheap insurance.

This morning I've been thinking about engine speed, more specifically how fast an engine can rev. In moving exhaust gasses quicker, lag would be decreased. Boost achieved quicker. This could be done with light weight pistons and flywheel. Also I have been thinking about zero gap or gapless rings to minimize blow-by and maximize compression. Improved efficiency, make more power with less boost ? In minimizing blow-by the oil would also stay cleaner and reduce wear on engine and turbo. I haven't even begun thinking about cam specs.

Well since I just bought a 2001 Audi S4 I've been thinking about it's 2.7L Twin Turbo V6. Has anyone looked into using K03 or K04 turbos on a Fiero 2.8?

Here are the compressor maps
K03-

K04-

[This message has been edited by KaijuSenso (edited 04-29-2008).]

Here is an interesting read from the VW forums on the K03 turbo. Basically the answer is it's too small for a 2.8L engine. The poster is an administrator for the forum named footose. He starts with the VW 1.8L engine and goes from there. This is the link: http://forums.generationdub...howthread.php?t=4207

Ok, so lets follow the guide then..

CID = engine displacement
RPM = maximum rpm
CFM = cubic feet per minute

1781cc = 109.8947 CID .. Roughly 110 Cubic Inches..

or

1.8L * 61.055 = 109.899 CID

So we'll say 109.90 CID

Pump that into our equation..

(109.90 x 6500) / 3456 = 206.698495370

So this means that our 1.8L engine will flow 206.70 CFM of air assuming 100% volumetric efficency (VE).

We have to assume for 80 to 90% VE (split the difference 85%) because its damned near impossible to get 100% (TurboABA knows this! lol)

206.70 * .85 = 175.695 CFM @ 85% VE

To compare the airflow requirement against the compressor map you will need to convert CFM to lbs/min by multiplying the corrected CFM by 0.069

175.70 x 0.069 = 12.1233 lbs/min


12.1233 lbs/min represents your x-axis value at 6500rpms on the map

You will need to plot several data points on the compressor map. I'm gonna use 1500, 2500, 3500, 4500, 5500, and 6500. Substituting the rpm values into the formula produces the following table (corrected to 85% VE)

RPM - CFM - lbs/minn

1500 - 40.540 - 2.80
2500 - 67.570 - 4.66
3500 - 94.600 - 6.53
4500 - 121.63 - 8.39
5500 - 148.66 - 10.26
6500 - 175.69 - 12.12

NOTE: Whenever you solve for the engine airflow requirements you can move the decimal over to the right one place you end up with the engine's horsepower. In our example moving the decimal one place to the right yields 121.12 horsepower for 1.8L engine w/ NO TURBO.


... Still Calculating next section ...

Of course, the K03 would have to be a twin turbo setup. Basically I've been toying with the idea to rebuild the 2 K03s in my Audi when I replace them (hopefully with K04s), then fitting them into my 2.8. Only thing is it seems like a lot of work and money for our old 2.8s when you could start with a better platform for cheaper.

I agree. Sell them on Ebay and get a nice single turbo. A T3 for a stock engine, K04 or T3/T4 hybrid on a strengthened engine. JMHO

Has anyone tried hooking up water cooling to a T3 turbo? I am trying to get my oil temps down. I've tried 2 oil coolers with fans mounted under the engine louvers, then tried mounting 1 cooler under the car between the front of the cradle and heat shield. I still get temps around 257* F when cruising at 70mph. Now I want to try hooking up coolant to the center section of the old T3. The tapped holes are there just plugged.

quote Originally posted by timgray: You will find a lot of people, specifically on RFT and the honda sites that believe that turbo lag is horrible and you will be laughed at if you have any so they try and mount the turbo right on the exaust headers and do everything they can to make it sit almost on top of the engine, making their life hard for no real good reason. Turbo lag CAN be a problem, it's more of a problem in a underpowered car getting most of it's HP from the turbo like a honda civic, Del Sol, and others and ONLY when racing 1/4 mile. Turbo lag is of no real concern on the street as seen by the STS turbo and mounting them over 6 feet away from the engine. Honestly mounting your turbo lower down by the cat will give you no performance problems. The Turbo on big engine cars when mounted what is considered close is farther away than that. Honestly do not worry about where to put the turbo, put it where it fits well and looks good for you. If you can figure out how to put it at the muffler location and plumb the air back easily then I really want to see your design. If done right that would be a stealthy installation of a turbo. On a side note, I have been looking at the air/water/air intercoolers out there. It requires a secondary pump, but you can locate the radiator for the intercooler to the front of the car and pipe back the water to the intercooler heat exchanger. They are not as efficient as a air/air intercooler but they have more mounting options.

I'm pretty sure that RFT as a collective is an advocate of properly sized turbochargers, which generally means you'll get some lag on the bottom end. Turbo placement is a matter of compromise. For me, every inch of exhaust tube is an inch that siphons heat from the exhaust stream and into the engine bay. Having a header that's short, equal length, and tightly packed is well worth it to me, even if it's more difficult to fabricate. IMO, the work is worth it, and you end up with greater effeciency of the entire system, because more energy is being being directed through the turbine. Not to mention the engine bay in our cars is huge. And what is the cost? More time maybe, things a little bit closer together?

quote Originally posted by maddoggie: This morning I've been thinking about engine speed, more specifically how fast an engine can rev. In moving exhaust gasses quicker, lag would be decreased. Boost achieved quicker. This could be done with light weight pistons and flywheel.

I've been thinking about this too. I was considering going to an aluminum flywheel because it would rev quicker, but its not that easy. RPM isn't why you have boost, its LOAD.

For instance, on a decline vs up an incline, you will have more boost on the hill than going down the hill. An auto with 2 speeds and very long gears will typically build boost quicker than a 5spd auto with much shorter gearing, all other things being equal.

So it becomes a balance of whether or not you want that heavy flywheel so there is more load, and therefore more boost sooner. This is also why Brake Boosting works. You don't vary the RPM much, you just add more load via the brakes and you build more boost.

quote Originally posted by Jncomutt: I've been thinking about this too. I was considering going to an aluminum flywheel because it would rev quicker, but its not that easy. RPM isn't why you have boost, its LOAD. For instance, on a decline vs up an incline, you will have more boost on the hill than going down the hill. An auto with 2 speeds and very long gears will typically build boost quicker than a 5spd auto with much shorter gearing, all other things being equal. So it becomes a balance of whether or not you want that heavy flywheel so there is more load, and therefore more boost sooner. This is also why Brake Boosting works. You don't vary the RPM much, you just add more load via the brakes and you build more boost.

This is a little bit different...In "brake boosting" you're spooling the turbo before you need to transfer that boost into usable HP. When working through the gears you're using the weight of the car as your brake. You could use your brakes to spool the turbo faster, but holding your brakes down while you're trying to move the rest of the car would just eat up HP. Using a heavier flywheel would be counter-productive in the same way. AND if your flywheel isn't heavy enough, you won't be able to build boost just by reving because energy isn't dissipated like in a torque converter, it's stored in the form of higher kinetic energy. Granted, you do get SOME of this energy back when you shift to a higher gear, but a much greater percentage is transferred into heat in your clutch versus a lower MOI flywheel/rotating assembly.

In the end it comes down to mass flow rate. The best way to keep your mass flow rate => spool => boost is to introduce more mass. IE, active anti-lag (fuel dump), and nitrous.

[This message has been edited by FastIndyFiero (edited 09-22-2008).]

So you're saying that load has no bearing on boost?

quote Originally posted by project34: On the "STS Turbo" website ( http://www.ststurbo.com ), it appears that their claim to fame of "lowest intake air temps in the industry" (which sounds like a good thing) is indeed due to where their turbo is located --- typically under the chassis --- rather than inside a hot engine compartment. I've never used an STS turbo, but on the face of it at least, it sounds interesting.

The STS website basically says that turbo lag is not an issue. If you read the reviews by owners on the Corvette forum, the turbo lag is HORRIBLE. Now to be honest, the owners that just drive them on the street love the performance and the lag is not an issue (though even they admit that there is a lot of lag). The ones that like to spend time at the drags are the ones that say it is more than you can live with.

quote Originally posted by couldahadaV8: The STS website basically says that turbo lag is not an issue. If you read the reviews by owners on the Corvette forum, the turbo lag is HORRIBLE. Now to be honest, the owners that just drive them on the street love the performance and the lag is not an issue (though even they admit that there is a lot of lag). The ones that like to spend time at the drags are the ones that say it is more than you can live with.

The lag they experiency probably has most to do with the same benefit the distance has on the intake charge taking effect on the exhaust, cooling. All those with turbo fieros have probably noticed that if the exhaust gets pretty hot, for instance while tuning, you can hear the turbos spool up eventhough the engine is just idling compared to when things are cooler. The exhaust cooling off on the way to the back of the car causes contraction of the spent gases in the same way cooling the intake charge does and that can lead to increased spool up time in addition to what is caused by the distance.

The turbos may also be sized for a happy medium as opposed to bottom end light to light draggers or high end performance for those who push the limits and expect the side effects of a turbo sized for top end, hince the term rolling starts for a race as a result.

More importantly, I'm sure the vettes with manual transmissions compared to those with automatic trannies have a different experience considering those with manuals can raise the turbine speed before engaging the clutch. The autos would need a torque converter to counter the lag. The factory turbo sunbirds had 2750 rpm stall converters. Lag is a function of proper turbo for the application, not engine size, that being said, Honda owners complaining of lag probably put a 400 hp capable turbo on their engine (thinking that's all it would take to achieve 400 hp) instead of the properly sized turbo for their engine specs.

Otherwise the rear mount turbo setup is effective when done right; http://www.v6z24.com/jbodyf...k-bound-t103854.html

quote Originally posted by Jncomutt: So you're saying that load has no bearing on boost?

No, I'm saying that using a heavier flywheel isn't nearly the best way to get your turbo to spool up faster, as it will have negative impacts on performance and reliability.

[This message has been edited by FastIndyFiero (edited 09-23-2008).]

quote Originally posted by timgray: Never do a boost install without a wastegate, they are cheap, easy to install and cheap insurance.

I found out this is good advice. My T3 always made the same boost and it came on around 3000 rpm consistently. Recently I changed to a homemade intake manifold as an experiment. Due to clearance problems I had previously removed the wastegate actuator and used a somewhat soft spring to hold the wastegate closed. During testing I found the wastegate stuck open after a run. I figured it was too soft a spring so I replaced it with a stiff one. Bad move. The car made 17psi and backfired. No damage that I can tell but scared me enough. Turns out the softer spring allowed the wastegate to open during boost thus acting as a wastegate controller. Funny the things you learn the hard way.

Bummed I cant find the time to continue on this, I haven't even touched my car all summer because of being so busy.. My garage has parts all over in it, and I had to take the time to document what I did so I dont forget when I can get back to it.

My point on turbo lag is simple... If you are racing the car at the track for money, then eliminate lag. if you simply want a turbo car to drive, Installing a turbo in your car is incredibly easy. the tune is incredibly easy, in fact from what I have seen, one of sinister performances "baseline" tunes would be good for a daily driver turbo install. No dyno time needed.

Even having a huge turbo lag time is fine for a street daily driver. Understanding this means you can shove that turbo way down under the engine with a small oil pump to return the oil back to the engine.. More importantly, it will open up ducting your air charge all the way to the front of the car to a HUGE intercooler (compared to what you can shove in the back of the car) and all the way back to the engine giving you the same effect that the Corvette turbos give them and incredibly low charge temperature. It simply gives you more options. If you are not racing, dont try to build with racing rules.


Also yes, TP does relate to boost. but at 75mph on a stock automatic Fiero you are running at 3500 rpm and at a Throttle position that does have the possibility to spool up the turbo. A turbo automatic Fiero really needs a 4t440 transmission upgrade to eliminate the possibility to be in boost when cruising above the speed limit on the highways. A buddy of mine had a Turbo mustang that ran in boost on the highway, This was stock from the factory, so it happens.

I also did not see anyone answer this. putting a turbo after the CAT is not a good idea, the cat is a significant restriction and will reduce boost.

[This message has been edited by timgray (edited 11-09-2008).]

Heres a question, Im building a 3800sc motor w/ the blower replace w/ a aluminum intake / w/ zzp ss headers that i want to run a t3t4 turbo off of. Im also plumbing for a power steering setup so here's the question. Can i use my power steering pump to cerculate that fluid throu the turbo instead of the engine oil?

Rick

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http://i252.photobucket.com...ec/2007_12240001.jpg

Interesting thought. Realize the turbo center section gets very, very hot. You would absolutely need to cool the oil somehow to keep the ps pump alive.

hydrolic fluid is not designed as a lubricant. I do not know if that would work. I certianly would run a small oil cooler in the air stream to help cool it if you did a closed loop like that.

quote Originally posted by Bozzie: Heres a question, Im building a 3800sc motor w/ the blower replace w/ a aluminum intake / w/ zzp ss headers that i want to run a t3t4 turbo off of. Im also plumbing for a power steering setup so here's the question. Can i use my power steering pump to cerculate that fluid throu the turbo instead of the engine oil? Rick

You would need to know the pressure range produced over the rpm range and if you ever threw a belt the bearings in the turbo would probably be wiped out before you could shut the engine down. The traditional approach is far more efficient, dependable and compact. Take it from me, ideas = a lot more time to finish the project. Take the best approach the first time and save yourself a lot of time from having to redo it later. I'm on my 3rd wk of turbo 3900 remodeling for a cleaner harness and exhaust rearrangement etc... and I'm still not done. It takes an awful lot of time to cut, shape, weld and solder. If I get it cranked again before putting it down for a couple of weeks Tuesday I'll be very, very fortunate as it doesn't appear that will happen. I am pleased with how it looks now and that makes it all worth the wait.

[This message has been edited by Joseph Upson (edited 11-10-2008).]

You do good work though. Looking forward to seeing your redesign.

Off the top of my head, there are 4 ways that you can ELIMINATE turbo lag, and it has nothing to do with the actual install dynamics (charge piping, exhaust manifolds, ect).

massive timing retard can be done on any setup at any time via ecu or user input
brake boosting
small nitrous
higher stall torque converter / anti lag 2step style

On turbo automatic 3800's a mild stall converter upgrade makes it so every setup I have seen has the ability to make nearly 12+ psi at a stop.

i have run my turbo both remote and directly bolted to the manifold and the amount of lag was about the same in both installs .what i did not like about the remote was the extra bolted joints that were prone to leaks and the difficulty in fitting everything under the trunk and stopping all the piping from sagging and breaking brackets .the cooling of the exhaust gases was not an issue as i heat wrapped everything .and the cat was before the turbo .cats have very little flow restriction and heat up the exhaust as it passes through .i am now doing a modded version of a direct mount turbo and with what i have learned should be my best setup .
everything fits nicely under the trunk and my charge pipe follows the path that the old v6 exhaust used to take :

quote Originally posted by maddoggie: Sounds great Hudini, I'm not quite sure about the wastegate part though. I see your logic and understand your aims, but I don't have enough guts for that comitment. Are you seeing boost at cruise speeds as Fog has discussed? The 3.4 and cam is very similar to what I am planning.

I am seeing 15 inches of vacuum at 75 mph cruise at 3300 rpm. This is with either spring on the wastegate. The funny thing is with the heavy duty spring I could get 15psi boost instantly by pressing the gas pedal down a bit further. It felt like 1/2 throttle. If ever I get all the parts together and the engine built for it, I'm going for better than 15 psi. The power it made was incredible.

Has anyone considered using the Garrett turbo charger that is water cooled. The ball bearing turbo has many options and a liquid cooling option. Would eliminate alot of plumbing problems for remote turbo systems and keep your engine oil out of the loop.

Rick

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http://i252.photobucket.com...ec/2007_12240001.jpg

Liquid cooled turbos still require lubrication from engine oil, or some other pressurized source.

This thread is AWESOME. I've spent the last hour reading through all the useful info.

I have a 3.4L Pushrod and I'd really like to turbo it - I've been thinking about it for the last 3 years.

Please keep adding to it!

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1986 Pontiac Fiero SE 3.4L | The Fiero Blog (Since April 2000)
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My Portfolio site | JustinChristie.ca

How does something like this:
http://cgi.ebay.com/ebaymot...IT&item=390004694697

look for a 3.4L w/Comp 260H cam and Focoa headers?

Too big? Too slow too boost?

I figure the twin-scroll would spool a bit faster with the proper cross-over set-up.

What do you think?

http://autospeed.com/cms/A_110904/article.html

An interesting way of tuning your turbo setup for today's cars with EFI.

It's basically the same thing they did back in the non EFI days when you took a carbed car and added a turbo to it. They are using a device to use the engine's vac/pressure in the intake manifold to adjust fuel delivery. Instead in this case, it's bleeding off MAP readings making the ECM think the pressure is lower than it really is.

Granted this is kind of a dirty "hack" to do this. but if someone cant afford to keep having a chip tuned, they can get a baseline from darth that will, if they gave him the right info, would run pretty good to start with. And then tune it in a little bit more after wards without using a laptop.

Remember, anything out there made for the ricer guys CAN be used in our cars. It may need to be adjusted or modified, but it can work if it's the right tool for the job.